| 摘要 |
PROBLEM TO BE SOLVED: To obtain a PTC composition which is kept stable in characteristics even if it is repeatedly used and excellent in reproducibility, by a method wherein specific weights of a metallic conductive filler, a crosslinking agent, and a specific fullerene are compounded with a crystalline polymer. SOLUTION: 100 pts.wt. of a high-density polyethylene resin, 300 to 550 pts.wt. of a metallic conductive filler, and 0.01 to 100 pts.wt. of a crosslinking agent are mixed together and uniformly dispersed, and thereafter 0.01 to 100 pts.wt. of a fullerene is added to the above mixture and kneaded into a conductive composition (positive temperature coefficient(PTC) composition). Then, the conductive composition is sandwiched in between the roughened surfaces of two nickel foils, which is pressed, rolled, thermally cured, and cut into unit annular PTC resistor elements. At this point, the metallic conductive filler is previously subjected to a surface treatment by the use of titanate compound coupling agent. An high molecular alloy where one or more kinds of thermoplastic high molecules are blended together is used as crystalline high molecules.
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